Tile over painted drywall

I believe the newer mastics have a form of aliphatic glue in them making them a good bodning agenet for this application.
You should google this to find out who make the type you will need in your area.Once the tile is grouted and sealed there should be neglible water vapor penetration.

Bob

as long as the semi-gloss is roughed up a bit(take of the gloss) you’re good to go. where I worked painting before tiling was preferred by the tile installers. If the tiles comes off it won’t be because of the paint. The question here is, is the paint sound? check the points of potential failure for soft(wet) drywall around the tub and sink, counter tops, anywhere where there are likely to be repeated spills or exposure to water. push on those points with a pencil or pen and compare to a dry area, if there’s moisture behind the paint you’ll know.

Ditto the comments above. I’ve tiled over a painted wall with good results.

-- Tim - http://www.tmuli.com